Compilare: user.cpp: In function ‘void solve()’: user.cpp:35:50: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < m && idx[i] < where[i].size() && idx[i + 1] < where[i + 1].size(); i++) ^ user.cpp:35:86: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < m && idx[i] < where[i].size() && idx[i + 1] < where[i + 1].size(); i++) ^ user.cpp:39:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (idx[1] < where[1].size()) { ^ user.cpp:41:52: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < m && idx[i] < where[i].size() && idx[i + 1] < where[i + 1].size(); i++) ^ user.cpp:41:88: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < m && idx[i] < where[i].size() && idx[i + 1] < where[i + 1].size(); i++) ^ user.cpp:46:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (idx[m] < where[m].size()) ^